Hypothermia is a highly effective treatment when applied to neonates suffering from birth asphyxia. Research reveals that damages following asphyxia can be curbed effectively by lowering the infant's body enough to induce a state of transient hibernation. Meta-analysis of a large number of randomized controlled trials show that hypothermia for 72 hours started within 6 hours of birth significantly increased the chance of survival circumventing brain damage. Incidences of neonatal encephalopathy occur at a frequency of up to 20 per 1000 births in developing nations. Thus there is a need to develop technologies to prevent neonatal asphyxia and complications that arise from it.
Treatment mandates a strict temperature control in the bandwidth of 33 to 34° C.
Indian patent application no. 23/2/DELPN/2005, discloses an apparatus for cooling a patient to a temperature below normal body temperature using an air cooling system which is of high cost.
Many inventors have proposed the use of phase change material composites to effect cooling.
Basically Phase change materials (pcms) store thermal energy in the form of latent heat and depending on the material used they can be exploited for thermal regulation in the required temperature range.
US patent application no. 2012/0330388 describes the thermal regulation system comprising conventional PCMs. However the solid pcms used in the invention are very hard to touch causing discomfort to the neonate and further the system is not leak proof thus making it unsuitable for neonatal use.
PCT Application number WO03061412 A3 relates to garments for heating or cooling a body part of a wearer of the garment. The cooling or heating layer comprises a flexible substrate having disposed thereon a two dimensional array of pockets containing phase changing material. But the invention focuses on garments in which can be stored bladders containing a phase change material, not an assembly for the effective cooling of neonates.
U.S. Pat. No. 8,257,417 B2 discloses a system comprising a temperature regulation element and a bedding element that includes a phase change material which changes between a liquid phase and a solid phase. However patent does not claim cooling and PCMs employed are not suitable in the effective temperature range.
U.S. Pat. No. 6,004,662 A discloses a PCM composite using multiple PCM's with different transition temperatures randomly distributed throughout the composite. It however, does not disclose a system to regulate the cooling of the bedding element and phase change materials enclosed in different compartments that are used in conjugation with an enclosure to form neonatal cooling device. It also does not specify PCM compositions effecting cooling and sustaining temperature in the range of 33 to 34° C.
It is thus an object of the invention to provide a device which can effect instant and sustained cooling of neonates in the temperature range of 33 to 34° C.
It is another object of the invention to use multiple sheets of reinforced form stable fatty acid and fatty acid ester based pcms functional at different temperatures to give a temperature gradient as in a cascaded system to effect and maintain hypothermia.
It is yet another object of the invention to have a portable and low cost model that is thermally conductive, leak proof, skin friendly and provided extended cooling without a requirement for continuous or frequent recharging so that device could be effectively used even in rural areas which do not have access to state of the art neonatal facilities.